There are known motor vehicles that comprise a hydraulic service brake system for the front and rear axles and a parking brake system with electromechanical parking brakes (EPB) on the wheels of the rear axle that can be activated by the driver by means of an EPB operator push button. An emergency braking function is also known in such brake systems, which has the effect that if the EPB operator push button is activated by the driver while driving, hydraulic braking is triggered by means of the service brake system in order to brake the vehicle with a preset deceleration. Said function is also known as a dynamic brake function (DBF). If the (hydraulic) dynamic brake function (DBF) is not available, the actuator dynamic brake function (ADBF) can be used as a fallback, with which the electric parking brakes (EPBs) on the rear axle are used for braking while travelling.
In the case of said known operating method, the front axle turns freely, i.e. is unbraked, and the rear axle is braked with the electric parking brakes. The known ADBF is only digitally activated or deactivated by the driver by operating the EPB operator push button, i.e. analog regulation of the provision of the clamping forces is not provided. In the case of a suitable operating command, the electric drives of the electromechanical parking brakes are energized in the clamping direction until a tendency to locking up of the EPB braked wheels can be detected. The energization is then reversed until the tendency to locking up no longer exists, in order to clamp again thereafter and to repeat said process cyclically. The rear wheels are thus braked by means of the electric parking brakes at the limit of stability thereof, i.e. with the maximum achievable deceleration effect.
The background description provided herein is for the purpose of generally presenting the context of the disclosure. Work of the presently named inventors, to the extent it is described in this background section, as well as aspects of the description that may not otherwise qualify as prior art at the time of filing, are neither expressly nor impliedly admitted as prior art against the present disclosure.